Data Mapping

Pollsters, public health officials, and marketing executives are among the many who use cartograms, special maps that provide a visual sense of geographic information by distorting it in proportion to a key variable. Researchers at AT&T labs in Florham Park, NJ, have created software that takes just minutes to calculate the distortion for thousands of regions (say, for all 3,066 U.S. counties), while old methods could take hours and could handle only tens of regions at a time. The AT&T technology reduces the computational job by imposing lines of various lengths and orientations across the map and performing size adjustments to the space on either side of each line. The process reconfigures geographic regions into recognizable but meaningfully transformed shapes without having to recalculate the whole map. Earlier cartogram programs used different approaches: Some treated the regions like balloons that inflated or deflated in a process that worked quickly but didn’t preserve recognizable shapes. Other software that treated the data as a series of mathematical equations produced more familiar and accurate shapes, but consumed hours of processing time. Daniel Keim, the new software’s lead developer, says AT&T began using it this year and researchers are refining it while the firm pursues licensing agreements.